Uh-oh. Greenland and Antarctica melting faster than expected

Greenland and Antarctica are the two ticking time bombs of sea level rise—no …

The rate of melting by the ice sheets covering Greenland and Antarctica may throw existing projections for sea level rise out the window. Unfortunately for Maldivians and other idyllic, but altitude-challenged islands, the ice sheets are melting faster than anyone expected.

Sea levels have been rising nearly unabated since the late 19th century, but rates have been increasing in recent years. The bulk of the change has been attributed to water expanding due to rising ocean temperatures, while melting ice in Greenland and Antarctica was considered to contribute a relatively small amount. But a new study published in Geophysical Research Letters reports the ice sheets may be contributing to sea level rise at a rate three times that which was previously suspected. The result? Sea levels could reach predicted heights 50 years earlier than experts thought, and total sea level rise may exceed previous estimates.

Ice is primarily lost from the Greenland and Antarctic sheets when it calves into the ocean. When ice sheets move faster toward the ocean, they shuck more ice into the water. And if snowfall over the ice sheets fails to replenish the amount lost, the sheet shrinks in size over time, transferring the water it once held into the ocean.

The new study used two independent approaches to arrive at the result. The first used interferometric synthetic aperture radar, commonly known as IfSAR or InSAR, from three satellites (the European Space Agency's ERS-1 and 2, Canada’s Radarsat-1, and Japan’s ALOS). These satellites can track the speed at which ice sheets move. In conjunction with radio echo sounding to determine depth of the sheet and regional weather models to estimate snowfall, the researchers determined how the amount of ice on Greenland and Antarctica was changing.

The second approach used NASA and the German Space Agency’s GRACE satellite system, which detects small variations in the Earth’s gravitational pull. Two identical GRACE satellites travel in the same orbit and use microwaves to calculate how far apart they are. Fluctuations in the Earth’s gravity, such as those caused by the loss of ice in Greenland and Antarctica, alter distance between the satellites subtly. They can detect shifts between themselves as small as 10 micrometers.

Using these approaches essentially allowed the researchers to verify their results. The researchers compared the same areas over the same periods of time for both ice sheets. The verification test produced results that were within 20 gigatons per year in Greenland and 150 gigatons per year in Antarctica, well under previously observed error estimates for each individual approach.

That both Greenland and Antarctica are melting faster than previously suspected—and therefore contributing more to sea level rise than expected—will certainly change estimates of sea level rise over the next century. Both ice sheets were expected to melt due to climate change, but experts anticipated the melting would occur later in the century. Given the pace of their current melting, sea levels may rise more quickly than experts had predicted and will likely overtop current end of the century estimates.

Quickly rising sea levels will give low lying areas less time to prepare. Results from the new study indicate 32cm of sea level rise by 2050, 15cm of which is attributable to the Greenland and Antarctic melting. Though one foot may not sound like much, a FEMA study (PDF) estimated storm surges under such a scenario would cause about 40 to 60 percent more damage than at present. That seems like small potatoes compared to the kinds of problems Bangladesh, the Maldives and many Pacific islands will likely face in just 40 years.

@exopuppy. Greenland and Antarctica are continents with ice on top of them. You are thinking of the north pole.. That ice isn't in the ocean - when it is the sea levels will rise. Again this problem is 100% solvable. We just don't want to do it.

Well, until industrialized countries radically change the way their societies operate, and until citizens of the first world realize they cannot live the gadget, gasoline and electricity driven ways of life they have come to expect... we are fucked.

I don't really think we will solve this... there is no political will. The world will change, we will struggle to adapt and largely fail, the future will probably be very bleak.

I realize that this study is looking at land-based ice/snow, but this site (http://nsidc.org/sotc/sea_ice.html) indicates that Antarctic Sea Ice (not from glaciers) has been increasing while Arctic Sea Ice has been decreasing. Given that the southern hemisphere has much more water content compared to the northern hemisphere, this cooling trend in the south is expected to follow in the north. We have been in a warming trend since the late 70's, but there are convincing signs that it will be reversing with a cooler PDO index. 2007 appears to be the low point and we have rebounded since then.

I'm not denying that warming has occurred for the past 30 years. I just don't share the opinion that we know all we need to know yet to determine that the "science is settled" and man is causing all of the warming. To say otherwise is to slap the face of proper scientific method and the quest to always learn more. If computer models could accurately predict the weather tomorrow, I would have more faith in them to predict 100 years from now. The smallest inputs, over time, can have great affects on the outcome. We are nowhere near the accuracy required for a correct forecast. Too many variables and too many unknowns that are being figured in. Past history shows us that the Earth has warmed and cooled many times with the influence of man. Does that mean that we should continue polluting and wasting resources? No, but neither should we panic and adopt knee-jerk reactions that would accomplish nothing except make some "carbon credit" traders wealthy. If Al Gore's message were so important, why was he charging $125,000 speaking fees? Clearly, he only wanted to profit from it. An altruist would speak for free, if it meant that much to him.

Well, until industrialized countries radically change the way their societies operate, and until citizens of the first world realize they cannot live the gadget, gasoline and electricity driven ways of life they have come to expect... we are fucked.

If we give up our Electricity driven ways how do we post on the internets?

"Well, until industrialized countries radically change the way their societies operate, and until citizens of the first world realize they cannot live the gadget, gasoline and electricity driven ways of life they have come to expect... we are fucked."

No. This isn't true. We have MASSIVE amounts of energy available in the form of nuclear power. Nuclear power (albeit indirectly) is the source for pretty much all 'alternative' fuels on earth. The simple solution is to build alot of nuclear power plants. In the US we are using alot of ancient aging nuclear power plants - 104 to be exact and they generate 20% of our power. If we simply built new modern plants (which are incidentally safer) we could generate most of our power with nuclear energy like France does.

Some of the next gen nuclear power plants can actually use our nuclear waste - and turn that into power. it's enough power to last us 100 years at our current rate of use.

'I don't really think we will solve this... there is no political will. The world will change, we will struggle to adapt and largely fail, the future will probably be very bleak.'

I agree there is no political will. But we will eventually deal with the results of MASSIVE global warming - probably via a belated switch to nuclear power. There is no will to build the plants now. They take a while to build and we would have to be cranking out around 1 per year to really stop the problem.

Ironically its the enviromentalists (like Gore) who actually caused this mess. Gore personally cancelled an advanced nuclear power program that we were funding which was on track to lead to very nice IV generation nuclear power plants. The problem with conservation is that it simply won't work. Even if you could convince EVERY american to cut personal power use by 50% sooner or later you will still reach those dangerous levels of CO2 and the global warming will happen.

If you believe (like most people do) that global warming can be easily charted and predicted by rising CO2 levels you begin to understand that the only real solution is stamping out CO2 production altogether. The earths abilty to deal with that excess CO2 is very limited.

The only solutions are alternative power sources that create zero carbon emissions. Of those the only really scalable one that provides baseline power generation is nuclear power. So the solution is simple - build alot of nuclear power plants. It can be done now using today's technology. It's just we don't want to do it.

Global warming is the biggest scam in history. It has been proven time and time again that the "data" used in things like this is skewed and incorrect.

The earth had "global warming" long before man walked the planet and humans are need to quit thinking so highly of themselves that they have this type of effect on the planet... it simply is another earth cycle and man has little to do with it.

So now all that blather about moisture in the atmosphere and ozone were complete bunk? Song and dances made up to try to explain away data that didn't match the models and directly contradicted the dire predictions?

Just because they have better larger estimates of melt rates does not mean the sea level rise rate is going to increase. If you have a big lake with a river flowing into it and you have been measuring an increase in level of 3 mm per year. You figure out your estimate of the river flow is too low say 50 gals per day instead of a better estimate of 100 gals per day. This does not mean the lake is now going to fill at 6 mm per year. All it really means that your models for the lake level increase are wrong.

I realize that this study is looking at land-based ice/snow, but this site (http://nsidc.org/sotc/sea_ice.html) indicates that Antarctic Sea Ice (not from glaciers) has been increasing while Arctic Sea Ice has been decreasing.

That doesn't affect rising sea levels, however - only land-based ice does that, and if this data is correct, we will have flooding irrespective of other climate change effects.

Science is NEVER "settled", fundamentally. Scientific principles (Method) are rooted in ancient Western philosophy, in which EVERYTHING is questionable—always, even against the status quo.

Chark, I'm with you 100%.

The real problem is 7 BILLION people on the planet this year, not whether waters rise less than half a meter. Waters could rise 2 meters and we'd be fine if we had HALF the population on the planet, which would still be too many of us! Anyone looked at a world population chart during just the 20th century alone??... It explains everything. Google it.

I vote for nuclear. Too bad we couldn't have kick started our economy, reduced foreign dependence, and reduced spewing carbon into the atmosphere with a 757 billion dollar nuclear power plant construction program back around March 2009. Instead we got nothing except debt.

"The only solutions are alternative power sources that create zero carbon emissions. Of those the only really scalable one that provides baseline power generation is nuclear power. So the solution is simple - build alot of nuclear power plants. It can be done now using today's technology. It's just we don't want to do it."

Yes, this is true. It's true of a lot of different potentially viable solutions to the problems facing humans and our planet, that the individuals and organizations that CAN do something are unwilling, sometimes due to shareholder or citizen pressures, and sometimes due to other factors (most of which stem from a lack of optimism and 'forward-thinking' in the people behind our major world players, like governments and multinationals, IMHO).

In this case, a huge influx of modern nuclear power facilities would do quite a bit to help alleviate our global energy problems, but, as you say, there is a lack of political will, stemming from (but not entirely due to...) public pressures to focus our resources on solutions to other, more short-term, problems.

I'd say that a more basic contribution to a solution can also be a greater emphasis, in these kinds of forums and online conversations, on positivity and optimism, coupled with grassroots encouragement of the average netizen, with regards to effective solutions to potentially massive global problems.

I'd like to see more discussions focused on trying to solve the problems in front of us, rather than litanies of the problems themselves ad nauseum, and the accompanying moaning and groaning about how bad a situation we're in (or that we've created for ourselves, depending on your views of the reasons for where we are).

Unfortunately, it seems like most people just like to complain. Your suggestion (RE one new reactor/year) is a potentially significant contribution to the solution - now people just need to either see how it can be made to work (ie. help change public opinions), or offer up other potential solutions (yes, with their attendant problems) and find how to make them work feasibly.

I vote for nuclear. Too bad we couldn't have kick started our economy, reduced foreign dependence, and reduced spewing carbon into the atmosphere with a 757 billion dollar nuclear power plant construction program back around March 2009. Instead we got nothing except debt.

Building a nuke power plant is one of the most greenhouse gas intensive projects that can be done, partly because creating cement and concrete produces CO2 at near fossil fuel burning levels.Just face it, we're doomed!

@Eric: Agreed you should believe very little of what the media feeds you and doubt is a reasonable response to any extraordinary claims. But you also can't ignore facts and data simply because they don't fit with your ideology or you're no better than the media you're attacking. Being dubious is good, being bigoted against all sources because a few are suspect is bad form. In a science forum it seems you will win more hearts and minds with sound rebuttal.

The real problem is 7 BILLION people on the planet this year, not whether waters rise less than half a meter. Waters could rise 2 meters and we'd be fine if we had HALF the population on the planet, which would still be too many of us! Anyone looked at a world population chart during just the 20th century alone??... It explains everything. Google it.

Amen. So many people talking about climate change, debating whether or not humans have anything to do with it.. and yet if you overlap population growth on top of climate numbers and the answer becomes more clear.

Luckily though, if the previous poster who indicated the majority of mankind lives near coastlines, then this problem should solve itself. Some may be able to move, but some won't -- some won't even acknowledge the risk I'm sure. If the countries with explosive population growth don't control themselves willingly, the planet will fight the infection and heal itself.

So, putting aside whether it is caused by human activity or not, where would a savvy investor buy land to see a significant return on investment on a 15 to 20 year timespan? Will Canada warm up noticeably for example? Will inland central florida get a new coastline, so it makes sense to buy a lot of currently low priced land there? How about inland California?

I read some estimates of sea level rise of 5mm per year. 20 * 5mm = 100mm = a bit more than 3 inches.

Bummer, it looks like no return on the investment until you, your children and possibly your grandchildren are dead.